[2005 G35 Sedan].The 15amp fuse (#77) in the IPDM that sends current to the ECM relay and from there to basically every critical sensor/component in the engine (i.e. ignition coils,valve timing control,mass flow sensor,cam/crankshaft pos. sensor, etc.) keeps blowing out thus making the car crank but not start. First I need to note that the first time i replaced the fuse i hooked up the computer and i was not given any problem codes. The car started and I had it on for about 10 minutes (did not move it though) then i shut it off then went back to it 1 hour later and it started but as i started baking up it blew the fuse again by the time i rolled out of my driveway so i had to push it back. So that's when my headache began. I started by switching sensors back and forth on the IPDM (I noticed you could do that since most of them have the same part #) to see if it was a sensor that shorted out starting with the ECM relay but nothing (fuse kept blowing when i would drive it out even though the time it took to blow was not consistent). I did the same thing to the 3 cooling fan relays since I notice that whenever the fuse blows the fans would kick in on high (for a moment I had the idea that whenever the fans would kick in to cool down the engine it would short out something and make that fuse blow) but i ended up removing all three cooling fans relays and the 40amp fusible link to those relays to make sure the fans did not kick in but still same result. So far what i noticed after blowing 8 fuses is that the time it takes to blow it not the same.The first time it took just me backing up but another time i was able to back up and drive it around a few blocks then i got home and (since its cold outside) i reved it up until it was pretty warm ("normal" op. temp of course) and then went back and forth on my drive was and sure enough it blows but i noticed it keeps doing it when it reverses but I'm not 100% sure if that was the case on all the times the fuse has blown but I wanna say I'm pretty sure since I cant remember it doing when i was on drive and i did drive it around unless i was lucky enough for the fuse to blow just in my driveway but i do know the first time it did it was when my wife was reversing to leave a store parking lot. PLEASE any help is appreciated other than I need to take it to the shop/dealer ($$$$) since it seems its a high possibility I just wanna make sure I did not overlooked anything before i do that.THX.

 

Sounds like you have a problem with run-on sentences

But that aside, it sounds like your having a wiring issue. Something is grounding when it shouldn't be. Loose connection? Wire cut?

If you have narrowed it down to only REVERSE (which it seems you have) you may look at the wiring of the transmission signals related to the IPDM. Look in the FSM - free online versions of it.

 

#77 fuse (15amp) keeps blowing. Tried everything and found a problem in my ecu plug. Number 1, 115, and 116 on the pin out are suppose to be ecu grounds but I'm reading no continuity on those wires. And I get 12v on my multimeter when I put one lead on my frame and the other to the #116 wire witch should be a ground. The ground wire seems to be getting arced off somewhere but just wondering if you were ever able to resolve your issues. I know this was posted like 5yrs ago but thought it was worth a try.

 

NEW ECU and key reprogram and it fixed everything!!!